There has long been a demand for coffee brewing apparatus which would permit one to prepare a cup or two of brewed coffee in a simple, economical fashion. Currently known apparatus of this type include some type of coffee basket for receiving the coffee grounds and brewing the coffee and a filter for separating the grounds from the brewed coffee. This apparatus is simply mounted or received on a cup or other suitable small vessel.
Examples of such coffee brewing apparatus are shown in the patents to Michielsen, U.S. Pat. No. 3,389,650, Rombouts, U.S. Pat. No. 3,094,917, Dale, U.S. Pat. No. 2,899,310, and Milano, U.S. Pat. No. 2,716,937.
Many of these prior art coffeemakers include an arrangement in which the coffee grounds are enclosed in a water permeable, disposable container which resembles a tea bag. The coffee grounds of sufficient quantity to make one cup of coffee, for instance, are encapsulated in a filter material which is disposable along with the grounds. The main objections to this type of approach is the fact that it is considerably more expensive to purchase coffee grounds which have been encapsulated in the filter material, and the quantity of coffee grounds cannot be varied. Alternatively, it is advantageous to purchase the coffee in the conventional 1 or 2 pound quantities and purchase the filter elements separately.
One of the principal problems involved in brewing small quantities of coffee is the difficulty in getting the hot water to become intimately associated with all of the grounds in order to obtain efficient extraction of the coffee. If a small quantity of coffee is placed in the basket of a conventional drip coffee maker or percolator, there is difficulty in wetting the grounds so that they do not simply float to the surface of the water with little extraction taking place. In addition, there is a tendency for the water to form channels through a thin bed of coffee, and extraction of coffee will be achieved in only limited areas of the bed of grounds. It is for this reason that most present approaches to the brewing of a cup or two of coffee in a drip coffeemaker involve the use of the encapsulated grounds as described above.
Another difficulty in regard to apparatus for brewing coffee directly into a drinking receptacle is the fact that such apparatus tends to be very unstable and would tip over very easily. The apparatus would be rather tall and would be placed in the top of a conventional coffee cup, as is illustrated in U.S. Pat. No. 3,615,708 to Abile-Gal. It would be preferable to provide brewing apparatus which would have a low center of gravity and which would reduce the tendency to tip over.